Re: Linux 2.6.39-rc3

From: Tejun Heo
Date: Thu Apr 14 2011 - 00:03:49 EST


Hello,

On Wed, Apr 13, 2011 at 07:33:40PM -0700, Linus Torvalds wrote:
> On Wednesday, April 13, 2011, Linus Torvalds
> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> > On Wednesday, April 13, 2011, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> >>
> >> Yes.  However, even if we *do* revert (and the time is running short on
> >> not reverting) I would like to understand this particular one, simply
> >> because I think it may very well be a problem that is manifesting itself
> >> in other ways on other systems.
>
> sorry, fingerfart. Anyway, I agree 100%.
>
> we definitely want to also understand the reason for things not
> working, even if we do revert..

There were (and still are) places where memblock callers implemented
ad-hoc top-down allocation by stepping down start limit until
allocation succeeds. Several of them have been removed since top-down
became the default behavior, so simply reverting the commit is likely
to cause subtle issues. Maybe the best approach is introducing
@topdown parameter and use it selectively for pure memory allocations.

Thanks.

--
tejun
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